China now NZ's biggest export market

China has overtaken Australia as New Zealand's biggest export market for the first time, buying more meat, dairy products and pine logs, while shipments across the Tasman have fallen.

New Zealand's trade surplus was $718 million last month for an annual deficit of $520 million, according to Statistics New Zealand.

The monthly surplus was almost twice the $373m forecast in a Reuters survey and the annual gap is smaller than the forecast deficit of $970m.

In the first quarter, exports to China jumped 32 per cent to $2.3 billion and imports rose 2.8 per cent to $1.8b, outpacing trade with nearest neighbour Australia, which took $2.2b of New Zealand's exports, down 7.3 per cent, and sent $1.5b of its produce across the Tasman, down 5.3 per cent.

The rise of China to become New Zealand's biggest trading partner underlines the importance of high-level delegations to Beijing, such as business and cultural mission led by Prime Minister John Key this month.

Exports to China have more than tripled since the signing of a free-trade agreement in 2008, while it is the largest source of foreign students and one of the fastest-growing sources of tourists.

The New Zealand dollar ticked up to 85.07 US cents after the trade data was released, from 84.96 cents immediately before.

Total exports in March from the same month last year rose 5.1 per cent to $4.4b, led by an 18 per cent rise in meat and edible offal.

Exports of logs, wood and wood articles rose 28 per cent to $336m, led by pine logs.

Shipments of milk powder, butter and cheese were little changed, rising 0.1 per cent, while petroleum products other than crude oil fell 89 per cent.